JLG sky trak mmv Service Manual page 499

2
1
3
5. To gain access to the ten relays located under the
operator's dash panel, remove the three self-drilling
screws (7) (one screw is not visible in figure)
securing the lower dash cover (8) to the front dash
(9). Remove the lower dash cover .
To gain access to the relay located under the engine
cover, open the engine cover.
9
8
7
6. Remove the suspect relay from the vehicle.
Model MMV Rev. 12/04
6
5
4
MM2911
MT2050
7. Apply the proper voltage to the relay coil, either 12V
or 24V depending on the relay coil voltage, at
terminal 86 (10 and 12) and attach the ground (-)
probe to terminal 85 (11 and 13), ground. An audible
click should be heard indicating that the relay is
functioning properly.
10
13
Testing Diodes
To test diodes in the electrical system, set your DMM dial
on R x1 setting and connect one lead to each side of the
diode. Note the reading on the DMM. Reverse the leads
and note reading. Your DMM should indicate a high or in-
finite resistance (no meter movement) when connected
one way and a low reading when connected to the other.
If both readings are high or infinite, the diode is open. If
both readings are low, the diode is shorted. Repeat test
on remaining diodes. If any diodes are shorted or open,
replace the diode.
Note: To test diodes in the alternator connect one lead
to the common side of the diode. Connect the other lead
to the other side of any of the remaining diodes. Take
note of the reading on the DMM. Reverse the leads and
note the reading. Repeat test on all diodes in the alterna-
tor. If any diodes are shorted or open, replace or repair
the alternator.
Electrical System
11
MN1820
12
MT3140
10.19